Bone conduction hearing aid unit



June l5, I1954 H. B. sHAPER BONE CONDUCTION HEARING AID UNIT Filed Feb. 25, 1949 Mlllugi 73 INVENTOR Harry ATl'ORN EY -between .003 to .007.

Patented June 15, 1954 BONE CONDUCTION HEARING AID UNIT Harry B. Shaper, Astoria, N. Y., assignor to Dyna-v Labs, Inc., a corporation of New York Application February 25, 1949, Serial No. '78,364

1 claim. 1

The present invention relates to a bone conduction hearing aid device.

Considerable dimculty has been experienced with hearing aid bone conduction units because of the lack of compactness and because they do not have eiiciency necessary to permit a satisfactory amount of energy to the cochlea with the audio energy available from past conducting amplifiers.

Furthermore, many units are very susceptible to damage upon dropping, pulling or accidental hammering.

It is among the objects of the present invention to provide a novel bone conduction hearing aid unit which will be quite durable and not be readily subjected to damage and the internal critical elements of which will not be subject to displacement or deformation upon dropping, pulling or accidental hammering.

Another object is to provide a bone conduction hearing aid unit which will be small and compact and readily manufactured at low cost and which will be highly ecient to transmit substantial energy to the cochlea with the normal milliwatts of audio energy available from a vest-pocket Still further objects and advantages will appear from the more detailed description set forth below, it being understood, however, that this more detailed description is given by way of illustration and explanation only and not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

In accomplishing the above objects it has been found most satisfactory to provide a construction in which the heavy part of the hearing aid device, or the magnet and its associated structures, is

attached to the head band and the armature is maintained mounted upon the casing and its movement in respect to the magnet structure limited by the guard plate.

The swivel joint of the head band is attached to the magnetic structure instead of the housing and the forces developed between the armature and the main magnetic assembly are transmitted to the bone structure by the casing.

As a result there is very little likelihood of dropping, pulling or accidental hammering, tending to permanently deform the armature, since on the preferred construction, the extreme movement of the armature is limited by the guard plate, for example, to as small a movement as In general, the unit consists of a cup-like casing, preferably of plastic material, with an adhesively attached cover. Through a central opening in the cover is positioned a ball socket connection between the hand bank and the back of the magnetic structure.

Mounted in the bottom of the cup-like casing is the diaphragm which is provided with fixed spacer or guard plates to prevent distortion or deformation thereof beyond the maximum desired limited movement thereof, for example, .005.

With the foregoing and other objects in View the invention consists of the novel construction, combination and arrangement of parts as hereinafter more specifically described, and illustrated in the accompanying drawings, wherein is shown an embodiment of the invention, but it is to be understood that changes, variations and modications can be resorted to which fall within the scope of the claim hereunto appended.

In the drawings wherein like reference characters denote corresponding parts throughout the several views:

Fig. 1 is a side perspective View showinga hearing aid bone conduction unit in accordance with the present invention, with a head strap. l Fig. 2 is a transverse vertical sectional view upon the line 2 2 of Fig. 1 upon an enlarged scale as compared to Fig. 1.

Fig. 3 is aperspective exploded or separated view of the combination or unit of Fig. 2.

Fig. 4 is a detail fragmentary side sectional view showing how electrical connection is made to said unit.

Referring to Fig. 1, there is provided a head band A, a head contact portion B, and the hearing aid bone conduction unit C which is mounted upon a swivel combination D. Y

The unit C, as best shown in Fig. 3, has a plastic cover E, a retainer sleeve F forming part of the swivel combination, a magnet assembly G, a diaphragm or armature H, a guard plate I, a main casing unit J and a plug-in connectionK with electrical wires leading to the vest pocket amplifier unit, not shown.

Referring specifically to Fig. 3, the casing J has va base 20 with the recesses 2l and 22 formed therein to receive the heads 2S and 24 of the screws 25 and 26. The central portion of the base 20 is provided with a platform 21 with the openings 28.

The two openings 28 receive the shanks 29 of the screws 3G, which are held inplace by lthe shoulders 3l. The recesses are then filled up by plastic material 32'so that a smooth face 33 with the conforming curvature 34 will it against the side of the head and in contact with the skull or mastoid bone.

At one end of the casing J there is a ledge 35, the ends of which extend into the recesses 36 in the side straight walls 31 of the casing J. The top of the ledge 35 is provided with the recesses 38V and 39.

The elongated recesses 39 communicate with the openings 40 (see Fig. 4), into which extends the prongs 4| of the plug K. Y

The recesses 38 receive screws-or rivets which. hold the plates 42 (see Fig. 4) in position. These downturned fingers 43. The fingers V43ccnt'act the recesses 44 in the prongs 4| ,;where..the,y ps0.-- ject into the recess 39.

It will be noted V(see Fig. Y3) that the end-'wall 50 of the casingJ is curved whereas the end Wall .5,;|i ispolygcnal so. as 'toiorm ajiiat surface 52 .for the .plug Theguard plate ltsinto the plastic receiver lJ with its, curvedpedges- 52 and .53 contactingthe inner curvedV faces 5.4 of thefwalls y5.0ia11d'55; of the ledge35. Y Y

The guard plate I has the openings-.56 receivclearance at ltfinrespect to the projection 99.

Aplates 42 are provided with)theinwardlybenmA .-gether*tof'formthe unit of Fig. 2.

and it also has an outwardly projecting sleeve 99 with a spring ring retainer |80 below which the ball IDI of the swivel arrangement D snaps.

The ball |8| has a stem |92 peened at |93 onto t the end Y|04 of the head band or strap A. Ham-,-

mering or violent motion of the ball I| Vwill re-V sult in its striking the back face |95 of the magnetc structure G (see Fig. 2) .Y The cover E is. recessed lat |961- wherefit is cemented to the side wallsv 59, and'31'of the casing J. It isalso recessed at llto receivethe heads 98 ofscrews 91. The cover Ealso has a The elements of Fig. 3 may be readily put to- When .so

' :assembledalthough the diaphragm or armature Y .H,.willdirectly .drive or vibrate theV skull or masmg: tht/.Screws 251'and '26. v The heads 23 and 24 Y ofl the screws 2,5.and 2tAv abut against the1 plate,

Thecentral portiongof the guard plate I- is providedwith an opening 5-1- through which projects Y Vthe platform 21 (see Fig. 3). The platrorm 2.'|

colritacts` andabutsf the central portionY 66'of the armature'or diaphragm H.

The diaphragm or armature H has the.` end .curved-edges and Bil-(see Fig. 3) ttingciosely against thecur-Ved faces 54 and 55 .of the interior ofthe,receptacleJ.l Y Y Y The central portion 680i the diaphragm H is vpartly severedby the.slots.69 from theperipheral portion or'rim 'irofsaid-armatureeH, The centralgprgtonof` the armature His provided with theopenings V||, which receive the kshanks 29.of

. the screws 30. The rim 'lil is providedewiththe .openings 'l2 which receivethescrews 25 `andli.`

Togspacevthearmature I-I from the guard plate',

I` and thev magnet assembly G, `the U-shapedrclps 13. which may be of brass, arev provided on. each endbtfthe armature These clipsarefformed of sheet brass'or copper of about 0.0i05" inthickness,v v`The clips. '|3-A will assurev propervr spacing at 14 on each sidelof the arma-ture YH. (see. Fig,.-.2r).

Thegmagnet Vassembly, G is V.formed of three -units soldered together, namely a backing plate 8D, a core 8| and an annulus 82 with :the solder- 'ingfA extending aroundthe wallsof the vannulus The annulus82: is recessed at .83.to receive the threaded tapped brass. sleeveI 84Vand it is also I .slotted atv 85 and recessed at V8|55to receive the tapped brass sleeve 81.*

The' wirecoil 88 is inserted between .the core 8| and-.annulus82 andthe lead-in wires extend toid'bone, nevertheless dropping or pulling or hammering on the swivel D will not deform or put any particular stress upon the diaphragm H.

The spacing; of the-.diaphragm Il.is;.controlled by the clips 'I3 while theguard plate lfwillafpre.-

`ventv permanent deiormation` of .sa-id armature; H.

This arrangement is muchv superior tosanrarrangement. infwhich the swivel D can contact. and

.act upon the diaphragm or rarmature H Tdirectly and it isalso'super-ior to af. construction in'whichY Y themagnet -Qeinstead of the armature "H, drives the casing where it is applied to the head'fork mastoid bone.`

Moreover, by providing a central swivel f-D, mounted directly `upon the magnet 4structure Q, a superior arrangementresults. Y Theunit'above described has an average ness level-per milliwatty of db. above threshold level.' Y

The unit when placed over the'mastoid` ofl one ear neverthelessstirmilates-the cochleaI ofb0th ears and gives the hea-rer a balanced .hearingteeling with most satisfactory amplication. The unitis designed` to cooperate; with hearing aid amplifiers of.v medium hearing .power andV when coupled tothefbone structureofithe mastioid, normal-listening loudness is obtained wit-h2.- fifto `5 milliwatts of one watt-otelectricalenergy;

The unit is designed to obtain maximumreiiiciency Lfrom-.f a fvery small magnet4 structurej .and

the. entire unit-y may` measureggina preferred-embodiment; 1.70.6.'5 longby: .1775 -Wide :by .5V-thick.

Thef-requency response will-be '100; 110119,09()

B..S.,with:maximum power, enablingzcapacity Vof 0,.'1,wattfandzangimpedanceof;50.or 120..'ohms.

The yg-uardzplate maybe 0.020Ufin thickness awhile the diaphragm maywbefDAO ini thickness.. The magnets are preferably made of an aluminum;-

nickel,falloy. .Y c Y, Y r

. Whilef .there has beenl hereindescribed, a pre;-

,ferred form of; the. invention', it: should; be lun:- V-derstoodgthat v.theisamefmay 'ber-alteredlin details and-in relative arrangement of. partswithinrthe scopeof `the-appendedcl'aim Y Y Y YHav-ing Vnow particularlydescribed and ascer-V a tained the nature of the-invention; -an'd inf-what 1 manner the;` same isf'tofberperformed, what is claimed 'is:. f f a Y A. compact small 1 sizehone conductionhearf ing aid unit; less 'liablev to damage; 'displacement or deformationl upon dropping, pulling craccidenc tal"hammering', of the type having 'a magnet structure with a headband -pivota-lly connected thereto and-having ancupbcasing withan farma# ture mounted :directly upon@ the: .b`ase-;thereof, lwhich basev -is .f to l Ycontact'fithe I .Iside off the vhead `of the-wearer,.zsaidtarmature beingfprovidedewith a guard plate to'limit itsjmovementto between loud'- Y 5 0.003" and 0.607", said unit including a cup-like casing of plastic material with an elevated central plateau in the interior base thereof and with an adhesively attached cover at the outer periphery thereof, said cover having a central opening, a head band having a ball socket male connection extending inwardly through said central opening into the casing, a magnet having a ball socket female sleeve connection inside of said casing and receiving said ball socket male connection, an armature mounted on and connected to the elevated central plateau on the bottom of the cup, a guard plate encircling said plateau and being positioned below the top of the plateau, and attachment means extending through and connecting said guard plate, magnet and armature at periphery thereof, said guard plate being pcstiened between the periphery of the armature and the periphery of the casing and said magnet structure being connected to the periphery o f the armature and being devoid of direct connecftion to the casing.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date Re. 22,658 Koch Aug. '7, 1945 2,459,325 Knowles Jan. 18, 1949 2,482,044 Vernier 1 Sept. 13, 1949 

